Vehicle brake shoe



ocLzz; 1940. J, C, MCCUN'E 2,218,615

VEHICLE BRAKE SHOE Original Filed Aug. 194, 1938 wl/99M y ATTORNEY imlEMIL

Patented Oct. 22, 1940 A i I 'I i UNITED STATES PATENT OFFICE rVEHICLEBRAKE snor:

Joseph C. McCune, Edgewood, Pa., assignor to The Westinghouse `Air BrakeCompany, Wilmerding, Pa., a corporation of Pennsylvania Originalapplication August 19, 1938, Serial No. 225,785. Divided and thisapplication May 31, 1939, Serial N: 276,638

2 Claims. Cl. (18S-251) This invention relates to brake mechanism fortion brake elements or discs, and the reference vehicle wheels and moreparticularly to a friction numerals 95 and 96 designate two annularnonbrake .element for use in such mechanism, the rotatable frictionbrake elements or discs interpresent application being a. division oi mycoleaved with the rotatable elements in concentric 5 pending applicationSerial No. 225,785, led Aug- Y relation therewith and with thenon-'rotatable 5 ust 19, 1938. brake element 95 arranged at one end ofthe As illustrated in the copending applicationl repile. v ferred to, adisc brake mechanism has been pro- Both the rotstebie and non-rotatablebrake DOSed COInDriSing annular rotatable and n0nr0 elements are shownin Fig. 5 encircling an axle tatabie, ring-like frictinn diSeS'SOarranged and 22 to which the rotatable brake elements 1| and. 10associated with a. vehicle wheel as to effect brak- 12 are secured inany desired manner (not shown) ing 0f Said Wheel Upon the diScS beingfOreed so as to turn with said axle. Ihe .non-rotatable into frictionalbraking engagement. In order brake elements 95 and 96 are supported incont0 provide most encient braking, the braking centric relation withthe rotatable-.brake .eiei5 diSeS are Often built 11p 0f differentmateriels, ments and held against rotation in any. desired 15 i. e.provided with a. tough frame like structure manner (not shown). Therotatable brake elecapable of 'a certain degree of deflection withoutments 1| and 12 are both provided-in theirbralrbreaking. and to thisstructure is secured in one ing faces with a plurality of radiallyarranged way or another the desired braking material slots 80, the sidewalls of which are adapted .Which may be a metal. n fibrous Structure 0r0f to act as a fan upon rotation of said elements 20 any other suitablematerial to provide the friotc force air between the rctatame andnon-rctional characteristics required. tatableI elements vwhen infrictional braking en- The principal object of the present inventiongagement tc dissipate heet from said elements is to provide a novelfriction disc brake element and t0 thereby provide most emcient brakingfor use in disc brake mechanisms, which element operation thereof. A, 25iS adapted t0 be readily and cheaply inannfae- The reference numeral 81designates a brake i tured and Which Will Provide emcient brakingcylinder device which is of an annular'ring-like and long life. form andwhich encircles the axle 22 adjacent the Other Objects and advantagesWill be apparent o ter face of the non-rotatable brake element from thefollowing more detailed description -oi slslirhebrcke cy1inder device isadaptedtc be 3c the invention. supported in any desired mannerl (notshown) In the eeenlnpenying drawing; Fig. 1 is an isoin concentricrelation with the brake elements metric view of one-half of a disc brakeelement and comprises e plurality cf smeucircular brake looking at thebraking face thereef and eOncylinders ||9 arrangedv in spaced relationin a structed in accordance with the invention: Figcircle around theaxle and with their axes paral- 35 2 is a View on an enlarged Scale Of8f Dertien 0f lel to the axis or axle 22 and in line with the nonthedisc brake 'element shown in Fig. 1, but lookrctatame element 95substantially midway being at the OPDOSite face thereef; FigS'- 3 and 4tween its inner and outer peripheries. The sevare sectional views takenonl the lines 3-3 and er1-a1 brake cylinders H9 are secured in spaced 404-4 in Fig- 2; and 5' iS a diagrammatic View relation by connecting webs|20. 40 0f a Dertien 0f 8 Simplified disc brake mecha' Each of the brakecylinders ||9 is provided f nismwith a bore in which there is disposedto operate For the purpose of illustrating one application a brakecylinder piston |22. This piston is pre.. 0f the invention, it iS ShOWnin the drawing a5- vided on its outer face with an outwardly exsociatedwith an annular non-rotatable brake eletending piston stem |30 lthe end,cf which 1s 45 ment 0I dise 0f d dise bra-ke mechanism 0f the roundedand adapted to engage the lnon-rotatable type which embodies one or morenon-rotatable element 95 The cuter face peach of the brake and rotatablebrake diSCS arranged t0 be moved cylinder pistons |22 is at all timessubject to atlIltO lictiOIial il'itelengagemelli fOr effecting mosphericpressure through the open end of ,-,0 braking 0f a rotating member,Snell 9S the axle the piston bore, while at the opposite side of each 50or wheel 0f a vehicle. This arrangement 0f piston there 4is provided apressure chamber |3| parts is illustrated in the simple, diagrammatic tcwhich filuidL under pressure 1s adapted tc be form of disc brakemechanism shown in Fig. 5 supplied for effecting movement of the pistonin of the drawing wherein the reference numerals the direction of thebrake elements. When the 1| and 'l2 designate two annular rotatablefricpistons |22 aif'e thus operated, they are adapted 55 to move thebrake elements into frictional interengagement to effect braking of theaxle 22. Fluid under pressure is adapted to be released from the chamberI3I in the several brake cylinder devices to relieve the pressurebetween the several brake elements, whereupon any suitable means (notshown) are adapted to return the -brake elements to their releasepositions in which The non-rotatable brake element 95 has a braking faceonly on the side adjacent the rotatable brake element 12, while thenon-rotatable brake element 96 is made up of two ring or disc-likeelements each 'of which is like the element 95, but which are arrangedin back to back relation to provide friction faces on the opposite sidesthereof for frictional braking engagement with the adjacent brakingfaces of both of the rotatable brake elements 1I and 12.

The non-rotatable brake element 95 and each of the two ring or disc-likeelements comprisingv the non-rotatable brake element 96 are identical instructure, each comprising two, like, oppositely disposed semi-circularsections arranged in end to end abutting relation and secured in suchrelation in any desired manner (not shown). The lines of divisionbetween these sections are shown in Fig. 5 of the drawing;

Each of the semi-circular sections embodied in l the non-rotatable brakeelements 95 and 96 is constructedv as shown in Figs. 1 to 4 of thedrawing and comprises a semi-circular backingplate |00 provided at itsopposite ends with ears |02 for the purpose of securing the halves ofthe brake element together andv for supporting said element by means andin a manner not shown.

'I'he backing plate |00 is made of any desired, relatively thin, toughmaterial, such as sheet steel, and mounted on one side of said plate isa substantially semi-circular brake shoe |0I arranged for frlctionalbraking engagement with the braking face of the adjacent rotatable brakeelement. The brake shoe IOI may be made of any desired friction brakingmaterial, but in the present embodiment of the invention is preferablymade of castiron.

Each of the semi-circular brake shoes IOI comprises a plurality ofarcuate sections |09 secured to the braking plate |00 by spaced,integrally formed rivet-like projections H0.

The adjacent ends of each-two shoe sections |09 are arranged at an angleto the radius of the element to avoid any possibility of interlockingwith the sidewalls of the slots 80 in the adjacent faces of therotatable braking elements 12 or 1| and are also spaced slightly apartas by slots II to minimize warping of the backing plates |00 during theprocess of manufacture, which will now be described.

Each of the Ybacking plates |00 is punched from sheet steelto thedesired size and shape and edge of larger diameter, both of whichfeatures are important factors in rigidly securing the shoe sections |09to the backing'plates |00, asl will be now described.

'I'he shoe sections |09 are cast from iron directly on to each backingplate |00. After the mold is made for molding the shoe sections |09 andrivet-like elements |0 on to the backing plate |00, the bacln'ng plateis placed into the mold with the smaller ends of the punched holes |I2at the side upon which the shoe sections are to Ibe cast. I'he cast ironis then poured into the mold to form the shoe sections on the one sideof the plate and from that side flows through the holes I I2 to theopposite side to form the button like rivets IIO.

When the molten cast iron strikes the relatively cool backing plate |00,the backing plate expands and moves in the mold relatively to the castiron in the mold cavities at the two sides of the plate and during thisexpansion shears part way through the base portions of the buttons H0,which are still in a plastic state. This shearing action provides themajority of the buttons ||0 with a substantially semi-circular shoulder||3 which laps over the backing plate |00, as shown, slightlyexaggerated for the purpose of clarity, in Figs. 2 to 4 of the drawing.In addition to these shoulders I I3, the portion of the button likerivets IIO engaging the lside walls of the holes ||2 in the plate |00 istapered, having a larger section at the side of the plate opposite theshoe sections than adjacent the shoe'sections, which also lact totightly bind the sho'e sections to and thus against movement away. fromthe plate.

Although upon` cooling the shoe sections |09 and backing plate I 00retain substantially the same relationship as obtained at the end of theexpansion of the backing plate, the slight difference in the coeiilcientof expansion of the two metals comprising the `backing plate and shoesections is taken advantage of in locating the punched holes ||2 in thebacking plate, so that the slight movement of the one metal relative tothe other upon cooling will effect a high degree of ybinding between thebutton like rivets I0 and the side walls of holes ||2 in the Steelplates |00, in various directions relative to the shoe sections. 'Ihisbinding action-in conjunction with the locking action of the taperedrivets I I 0 and the shoulders H3 formed on the ends thereof secure theshoe sections |09 to the backing plate so tightly as to provide ineffect an integral structure.

By making the shoe |0| in a number of spaced sections |09 as abovedescribed, vwarping of the backing plate |00 and consequently of theshoe, which would otherwise occur, is avoided.

After the sections of the non-rotatable elements are made, as justdescribed, the cast faces of the shoe sections |09 are ground in orderto remove surface irregularities or the like thereon,` while the ends ofthe rivet like buttons I l0 are ground off to a predetermined lengthmeasured from the backing plate |00'.

'I'he ends of the rivet like buttons ||0 are ground oil as justdescribed for two reasons. One reason is that in the non-rotatableelement 95 certain of these buttons ||0 are arranged to engage certainspaced portions of the brake cylinder device B1 for defining the releaseposition of said element above described. Another reason is that in thenon-rotatable element 96 the buttons |I0 in the two backing plates |00making up this element, engage each other so as to support theoppositely disposed brake shoes |0| against collapse when subjected ontheir outer faces to braking pressures from the rotatable brake elements12 and 1|. With the brake shoes and backing plates |00 of thenon-rotatable element 96 thus supported in spaced relation, a relativelyfree circulation of air is permittedbetween the two backing plates |00thereof, as a Vehicle carrying the brake mechanism is moving along atrack, and this prevents the transfer -of heat, incident to braking,between said brake shoes and also carries away said heat and thusmaintains the temperature of said brake shoes at a sufficiently lowdegree to provide ecient braking. The rivet like buttons ||0 are also soarranged as to be out of alignment with the brake cylinder piston stems|30 when the two sections making up the non-rotatable brake element 95are secured in working relation with the brake cylinder device 81 asshown in Fig. 5, due to which said piston stems are adapted to directlycontact and work against the backing plate |00 of said element.

It will be apparent from the above description, that the improved brakeelement is relatively simple and light weight in construction and cheapto' manufacture.A The backing plate |00 being made of a tough andsomewhat bendable material, such as sheet steel, insures againstbreakage of the element, while the multi section cast iron shoe |0| alsocontributes to prevent breakage of said shoe due to distortion Vof theelement which may occur in use. By using the steel backing plate for-carrying the brake shoe |0|, said shoe may be made from cast iron whichprovides the desired frictional characteristics to produce eiiicientbraking of vehicles such as employed in railway service.

While one illustrative embodiment of the invention has been described indetail, it is not my intention to limit its scopeto that embodiment orotherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A braking element for a disc brake mechanism comprising an annular,ring-like metal backing plate having a radial face and a plurality ofthrough openings arranged in predetermined relation around'` andradially. of said face and opening at said face, a cast metal brake shoecast on said plate against said face and comprising a pluralityofsections spaced from each other and each section having a plurality ofintegral por-- porting said shoes and plates in spaced relation topermit the flow of cooling medium 4between said plates.

JOSEPH C. MCCUNE. J

